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Routines |
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Builds the graphic of the item that is carried by the ship in the buffer at ShipWorkArea_Carried (six bytes to a row) and clears the part of the screen beside the ship where the item will be drawn. Each byte of the sprite of the item is looked up in the shift table at CopyGameDown and combined with the buffer using XOR.
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| BuildCarriedItemGraphic | 43575 | LD HL,44923 | The sprite tables. | |
| 43578 | LD A,(51460) | The item the ship is about to pick up. | ||
| 43581 | AND %00001111 | Keep the bits of A that are set in 15. | ||
| 43583 | LD C,A | C=A. | ||
| 43584 | CALL GetTableEntry | Call GetTableEntry. | ||
| 43587 | EX DE,HL | Swap DE and HL. | ||
| 43588 | LD A,(DE) | Read DE. | ||
| 43589 | LD B,A | B=A. | ||
| 43590 | LD (23583),A | The width of the carried item. | ||
| 43593 | INC DE | Advance DE. | ||
| 43594 | LD A,(DE) | Read DE. | ||
| 43595 | LD (23584),A | Update the segments still to draw. | ||
| 43598 | LD C,A | C=A. | ||
| 43599 | LD HL,63162 | The carried picture in the ship work area. | ||
| BuildCarriedItemGraphic_Row | 43602 | PUSH HL | Stash HL on the stack. | |
| BuildCarriedItemGraphic_Column | 43603 | PUSH BC | Stash BC on the stack. | |
| 43604 | LD B,252 | B=252. | ||
| 43606 | INC DE | Advance DE. | ||
| 43607 | LD A,(DE) | Read DE. | ||
| 43608 | LD C,A | C=A. | ||
| 43609 | LD A,(BC) | Read BC. | ||
| 43610 | XOR (HL) | Flip the bits of A that are set in the byte at HL. | ||
| 43611 | LD (HL),A | Write A where HL points. | ||
| 43612 | INC B | Advance B. | ||
| 43613 | INC HL | Advance HL. | ||
| 43614 | LD A,(BC) | Read BC. | ||
| 43615 | XOR (HL) | Flip the bits of A that are set in the byte at HL. | ||
| 43616 | LD (HL),A | Write A where HL points. | ||
| 43617 | POP BC | Bring BC back off the stack. | ||
| 43618 | DJNZ BuildCarriedItemGraphic_Column | Decrease B and jump to BuildCarriedItemGraphic_Column until none remain. | ||
| 43620 | POP HL | Bring HL back off the stack. | ||
| 43621 | LD A,(23583) | The width of the carried item. | ||
| 43624 | LD B,A | B=A. | ||
| 43625 | LD A,6 | A=6. | ||
| 43627 | CALL AddAToHL | Call AddAToHL. | ||
| 43630 | DEC C | Step C back. | ||
| 43631 | JR NZ,BuildCarriedItemGraphic_Row | Jump to BuildCarriedItemGraphic_Row if the zero flag is clear. | ||
| 43633 | LD HL,(51458) | Fetch the word at 51458 into HL. | ||
| 43636 | CALL GetScreenAddress | Call GetScreenAddress. | ||
| 43639 | LD A,(23584) | The segments still to draw. | ||
| 43642 | LD B,A | B=A. | ||
| 43643 | INC L | Advance L. | ||
| BuildCarriedItemGraphic_Clear | 43644 | LD (HL),0 | Store 0 at the address in HL. | |
| 43646 | INC L | Advance L. | ||
| 43647 | LD (HL),0 | Store 0 at the address in HL. | ||
| 43649 | INC L | Advance L. | ||
| 43650 | LD (HL),0 | Store 0 at the address in HL. | ||
| 43652 | INC L | Advance L. | ||
| 43653 | LD (HL),0 | Store 0 at the address in HL. | ||
| 43655 | DEC L | Step L back. | ||
| 43656 | DEC L | Step L back. | ||
| 43657 | DEC L | Step L back. | ||
| 43658 | CALL MoveUpARow | Call MoveUpARow. | ||
| 43661 | DJNZ BuildCarriedItemGraphic_Clear | Decrease B and jump to BuildCarriedItemGraphic_Clear until none remain. | ||
| 43663 | LD A,(23612) | The scroll-in flag. | ||
| 43666 | AND A | Return if A is not zero. | ||
| 43667 | RET NZ | |||
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Continue on to AttachItemToShip.
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| Prev: 43559 | Up: Map | Next: 43668 |